Distributed process control systems, like those used in chemical, petroleum or other process plants, typically include one or more process controllers communicatively coupled to one or more field devices via analog, digital or combined analog/digital buses. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure, level and flow rate sensors), are located within the process environment and perform process functions such as opening or closing valves, measuring process parameters, etc. Smart field devices, such as the field devices conforming to the well-known Fieldbus protocol may also perform control calculations, alarming functions, and other control functions commonly implemented within the controller. The process controllers, which are also typically located within the plant environment, receive signals indicative of process measurements made by the field devices and/or other information pertaining to the field devices and execute a controller application that runs, for example, different control modules which make process control decisions, generate control signals based on the received information and coordinate with the control modules or blocks being performed in the field devices, such as HART and FOUNDATION® Fieldbus field devices. The control modules in the controller send the control signals over the communication lines to the field devices to thereby control the operation of the process plant.
Information from the field devices and the controller is usually made available over a communication network to one or more other hardware devices, such as operator workstations, personal computers, data historians, report generators, centralized databases, etc., typically placed in control rooms or other locations away from the harsher plant environment. These hardware devices run applications that may, for example, enable an operator or engineer to perform functions with respect to the process, such as changing settings of the process control routine, modifying the operation of the control modules within the controllers or the field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for the purpose of training personnel or testing the process control software, keeping and updating a configuration database, etc.
As an example, the DeltaV™ control system, sold by Emerson Process Management, includes multiple applications stored within and executed by different devices located at diverse places within a process plant. A configuration application, which resides in one or more operator workstations, enables users to create or change process control modules and download these process control modules via a data highway to dedicated distributed controllers. Typically, these control modules are made up of communicatively interconnected function blocks, which are objects in an object oriented programming protocol that perform functions within the control scheme based on inputs thereto and that provide outputs to other function blocks within the control scheme. The configuration application may also allow a configuration designer to create or change operator interfaces which are used by a viewing application to display data to an operator and to enable the operator to change settings, such as set points, within the process control routines. Each dedicated controller and, in some cases, one or more field devices, stores and executes a respective controller application that runs the control modules assigned and downloaded thereto to implement actual process control functionality. The viewing applications, which may be executed on one or more operator workstations (or on one or more remote computing devices in communicative connection with the operator workstations and the data highway), receive data from the controller application via the data highway and display this data to process control system designers, operators, or users using the user interfaces, and may provide any of a number of different views, such as an operator's view, an engineer's view, a technician's view, etc. A data historian application is typically stored in and executed by a data historian device that collects and stores some or all of the data provided across the data highway while a configuration database application may run in a still further computer attached to the data highway to store the current process control routine configuration and data associated therewith. Alternatively, the configuration database may be located in the same workstation as the configuration application.
Presently, configuration applications typically include a library of template objects or items, such as function block template objects and, in some cases, control module template objects. These configuration applications are used to configure a control strategy for a process plant and to provide display views at user interfaces of a process plant. The template objects all have default parameters, settings and methods associated therewith. The engineer using the configuration application can select these template objects and essentially place copies of the selected template objects into a configuration screen to develop a module, e.g., a control module. During the process of selecting and placing the template objects into the configuration screen, the engineer interconnects the inputs and outputs of these objects and changes their parameters, names, tags and other properties to create a specific control module for a specific use in the process plant. After creating one or more such control modules, the engineer may store the created module in the library or in a configuration data storage area. The engineer can then instantiate the control module (e.g., cause an executable file corresponding to the control module to be created) and download it to the appropriate controller or controllers, field devices, and other process elements for execution during operation of the process plant.
Thereafter, the engineer generally creates one or more displays for operators, maintenance personnel, etc. within the process plant by selecting and building display objects in a display creation application. These displays are typically implemented on a system wide basis in one or more of the workstations and provide preconfigured displays to the operator or maintenance persons regarding the operating state of the control system or the devices within the plant. Typically, these displays take the form of alarming displays that receive and display alarms generated by controllers or devices within the process plant, control displays indicating the operating state of the controllers and other devices being controlled within the process plant, maintenance displays indicating the functioning state of the devices within the process plant, etc. These displays are generally preconfigured to display, in known manners, information or data received from the process control modules, devices, or other process elements within the process plant. In some known systems, displays are created through the use of objects that each have a graphic associated with a physical or logical element, and that are each communicatively tied to the physical or logical element to receive data about the physical or logical element. An object may change the graphic on the display screen based on the received data to illustrate, for example, that a tank is half full, to illustrate the fluid flow measured by a flow sensor, etc.
Similar to the control configuration application, a display creation application may have template graphical display items, such as tanks, valves, sensors, operator control buttons like slide bars, on/off switches, etc. which may be placed on a screen in any desired configuration to create an operator display, maintenance display and the like. Template graphical display items may be stored in a template library along with configuration objects, or may be stored in a different template library. When placed onto the screen, individual graphic items may be interconnected on the screen in a manner that provides some information or display of the inner-workings of the process plant to different users. However, to animate the graphic display, the display creator must manually tie each of the graphical items to data generated within the process plant, such as data measured by sensors or indicative of valve positions, etc. by specifying a communication link between the graphic item and the relevant data source within the process plant. Moreover, once a display is created, it remains static in its configuration and layout.
While the control template objects within the control configuration application and the display items within the display creation application are convenient because they can be copied and used to create many different control modules and graphical displays, there is often a need to create numerous of the same control module and graphical display for different equipment and displays within the process plant. For example, many medium to large sized process plants have numerous instances of the same or similar equipment that can be controlled and viewed using the same basic general control modules and displays.
To address this problem, U.S. Pat. No. 7,043,311 (the entire disclosure of which is hereby expressly incorporated by reference herein) discloses a process plant configuration system that uses class objects also called module class objects (and generally referred to herein as class objects or classes) to enable a user to create numerous control modules, unit or equipment modules, or display modules from a common module class object. These control, equipment or display modules are created as instances of the module class or class object and include all of the features and properties of the module class object, thereby making it easier to create a number of similar control, equipment or display objects from a single or common class module object. Instances may, in turn, have their own children objects, so that objects may have multi-generational or multi-level relationships.
Currently, when an engineer makes a change to the configuration of one of the objects (e.g., the engineer changes one of the default parameters, settings or methods associated therewith, adds or deletes a parameter, etc.), the engineer saves the updated configuration of the object and downloads the updated configuration to a display application or controller to execute the updated configuration during run-time. When multiple objects are dependent on each other (e.g., when a second object references a first object or the second object is referenced by the first object), the engineer manually identifies the dependent objects and coordinates downloads for each of them to occur so that both objects are updated accordingly prior to executing the objects during the next run-time cycle. For example, when a first and second object corresponding to two devices in the process plant are dependent on each other and the configuration of one of the objects is updated, the engineer identifies and updates the configuration of the other object and then downloads the two objects simultaneously or in conjunction with each other. Then, the engineer identifies modules corresponding to the devices and downloads objects corresponding to the modules. Still further, the engineer may identify display views corresponding to the devices and modules and may download the objects corresponding to the display views. This process is tedious, time consuming and may be fraught with error.
Moreover, when an engineer makes a minor change to one of the objects, such as a change to a parameter value within the object without adding or deleting a parameter or affecting run-time logic, the engineer must save and download the entire updated configuration of the object to a display application or controller to execute the updated configuration during run-time. This may disrupt the execution of the object's run-time logic and may take up valuable bandwidth over the communication network when downloading the entire updated configuration. For example, to make the minor change, online operation may need to be stopped before the modified object is downloaded and then executed when online operation is resumed.